Supervisory system in communication system

Abstract

 In a communication system wherein repeater stations (C,, C₂, ...) and terminal stations (A, A', B,, B₂, B,) are connected in tandem, a supervisory system in which a logical hierarchical configuration is used for the transmission of supervisory information regarding the stations and a redundant polling is used to easily and securely collect the supervisory information from the slave or repeater stations (C,, C₂, ...) or the like. Whereby, if faults occur in some of the stations, the collection of the information is carried out without interruption and without the need to install a special information collecting line.

Description

BACKGROUND OF THE INVENTION

I) Field of the Invention

[0001] The present invention relates to a supervisory system in a communication system wherein a plurality of unattended repeater stations and attended terminal stations, each of which is ranked as a central master station, a master station, and a slave station, are connected in a tandem arrangement, the stations are constituted with a logical hierarchical configuration for processing supervisory information, and the supervisory information of the slave stations is easily collected.

2) Description of the Related Art

[0002] In a communication system such as a telephone exchange network, a data transmission system is known wherein terminal stations located in urban areas are interconnected through a plurality of unattended repeater stations by, for example, optical cables or the like, so as to form a tandem link, and audio data is transmitted at a speed as high as 400 Mb/s. In such a system, the distance between the repeater stations is several tens of kilometers, supervisory information or the like at each repeater station is collected at the terminal stations or supervisory information or the like at each of the repeater stations and the terminal stations is collected at a central station, the information collected at the terminal stations or the central station is analyzed, a faulty portion thereof is distinguished, maintenance is carried out and the system is restored.

[0003] In the above-mentioned data transmission system, lines for collecting information are installed between each repeater station and a terminal station or between each repeater station and a central station, and remote supervision is performed by collecting supervisory information at the repeater stations or the terminal stations at the terminal station or the central station, respectively. However, since special lines for collecting the information, other than the data transmission lines, must be laid, the disadvantage of higher line costs is incurred.

[0004] Another disadvantage is that in which, when the supervisory information or the like is collected at the cental station through the line for collecting the information and through the terminal station, if a fault occurs at the terminal station, the supervisory information from the repeater station collected at the terminal station cannot be collected.

[0005] The present invention is proposed to alleviate the above-mentioned conventional disadvantages.

SUMMARY OF THE INVENTION

[0006] An object of the present invention is to provide a supervisory system in a communication system constituting a link connected in tandem with unattended repeater stations and terminal stations, wherein the collection of supervisory information is performed by arranging the stations in a logical hierarchical configuration and using a double polling from master stations to slave stations, whereby the supervisory information can be collected at the different master stations and if one of the terminal stations malfunctions, a higher ranked station can properly collect the supervisory information. Another object of the present invention is to provide a supervisory system having an economical constitution wherein the installation of special lines for supervision is not necessary since the collection of the supervisory information is performed by polling through the tandem link.

[0007] In the present invention, in order to accomplish the above-mentioned objects, there is provided a supervisory system in a communication system having a plurality of repeater stations, a plurality of terminal stations, and transmission lines, and the repeater stations and the terminal stations are connected in tandem through the transmission lines. In the system, each of the repeater stations and the terminal stations is provided with respective supervisory equipment, part of the supervisory equipment being used as a master station and the remaining portion of the supervisory equipment being used as a slave station; one of the supervisory equipment provided as a master station being used as a central master station, and the supervisory equipment is arranged in a logical hierarchical configuration. The slave station located between the master stations is polled therefrom and the slave station transmits the managing supervisory information therein to the respective master stations. The central master station polls each of the master stations, and the master station transmits the collected supervisory information to the central master station.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] 

Figure IA is a diagram showing a communication system including terminal stations, repeater stations, and a central station to explain a principle of the present invention;

Fig. IB is a diagram showing the system in Fig. IA in a hierarchical configuration, to explain a principle of the present invention;

Fig. 2 is a block diagram showing a constitution of a communication system to which the present invention is applied;

Fig. 3 is a block diagram showing a main portion of the functions of a master station in a supervisory system in a communication system according to an embodiment of the present invention;

Fig. 4 is a block diagram showing a main portion of the functions of a slave station in a supervisory system in a communication system according to an embodiment of the present invention;

Fig. 5A, Fig. 5B, and Fig. 5C are block circuit diagrams showing a connection relationship between the functions in Fig. 3 and Fig. 4 and the communication system in Fig. 2;

Fig. 6 is a block diagram showing a connection relationship between the functions in Fig. 3 and

Fig. 4;

Fig. 7 is a diagram explaining a constitution of a supervisory system in a communication system according to an embodiment of the present invention;

Fig. 8A and Fig. 8B are diagrams explaining network managing tables in the supervisory system in Fig. 7;

Fig. 9 is a block circuit diagram showing details of the supervisory system in Fig. 7;

Fig. 10 is a diagram explaining basic frames in the supervisory system in Fig. 7;

Fig. II is a diagram explaining an MDATI frame in the supervisory system in Fig. 7; and,

Fig. 12 is a diagram explaining a sequence of the transmission of the supervisory information in the supervisory system in Fig. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention is now explained with reference to Fig. IA and Fig. IB.

[0010] In the Figures, assume that the repeater station or the like is represented as a slave station Cj (j = I, 2, 3, ...), the station A among the terminal stations represents a central master station, and the other terminal stations are represented as a master station Bi (i = I, 2, 3 ...), and that these stations A, Bi, and Cj are physically connected in tandem and constitute a tandem link. These stations are constituted in a logical hierarchical configuration for the supervisory information, as shown in Fig. IB. Reference mark A' shows a function positioned in the same hierarchical position as the master station Bi in the central master station A. The master stations A' and Bi transmit an information collection command to the slave stations Cj in the predetermined range by polling them through the tandem link. For example, the master station B, polls the slave stations C, to C₄, the master station A' polls the slave stations C, to C, , the master station B2 polls the slave stations C_s to C,, , and the master station B_j polls the slave stations C. to C,,. Accordingly, a double polling is performed on the slave station Cj, and the slave station Cj sends the information in accordance with the information collection command. The central master station A polls the master stations Bi and A', and collects the information collected at each master station.

[0011] By constructing the communication system so that the repeater stations, the terminal stations, and the like are physically connected in tandem to a logical hierarchical structure, and by double polling the slave stations, if one of the master stations malfunctions, since another master station has collected the supervisory information or the like from the slave station, the collected information can be transmitted to a higher ranked station, and thus the remote supervisory function can be ensured. Since the polling is performed through the tandem link, a special line for collecting the information, different from the data transmission line, is not necessary.

[0012] An embodiment of the present invention will now be explained in detail with reference to the drawings.

[0013] Figure 2 is a block diagram showing a constitution of an example of a communication system (405 Mbit/s SM (single mode) optical system) to which the present invention is applied. In the figure, LPSW denotes a line protection switch; LTE a terminal station; REG a regenerator (a repeater); BER MON a bit error rate signal monitor; SVOW INF a supervisory signal multiplexer; S-SV a slave supervisor; M-SV a master supervisor; MM-SV a central master supervisor; OW an order wire signal transmitter; LTE (NOR) terminal station for normal operation; and, LTE (STBY) a terminal station for standby operation.

[0014] In Fig. 2, S-SV corresponds to C, to C₁₁; M-SV corresponds to B, to B,; and MM-SV corresponds to A, in Fig. lB.

[0015] Figure 3 is a block diagram partially showing a constitution of a master station or a central master station according to an embodiment of the present invention, and shows the supervisory function thereof. In the figure, block I denotes a collection data management function; block 2 a connection link protocol sequence for collecting supervisory information at each station in SL (single-link) mode; block 3 an ML (multi-link) mode protocol analysis; block 4 an ML mode protocol sequence for collecting supervisory information collected at each master station ; block 5 a supervisory data display; block 6 an SV (supervisory) system display; block 7 a control operation display; block 8 an equipment alarm output; block 9 a slave station data transmission for transmitting commands to each slave station and receiving supervisory information from each slave station; block 10 a master station data transmission for transmitting commands in ML mode to each master station and receiving supervisory information from each master station; and block II a line protection operation display. The above-mentioned blocks I to 4 are constituted by a microprocessor and memories. Each of the above blocks is interconnected through a bus. The ML - (multi-link) mode protocol sequence 4 must be provided for the central master station A in Fig. IA and Fig. IB, but is not always necessary in the other master stations B, to B₃ , because this carriers out to collect supervisory information collected at each master station.

[0016] A transmission/reception for transmitting or receiving audio data or the like is not shown in the Figure. In this transmission/reception, an information collection command or supervisory information is multiplexed or demultiplexed, on a time sharing basis, to or from audio data as a main signal. In the SL mode, the slave station data transmission 9 outputs the information collection command to the slave stations and receives the supervisory information from the slave stations under the controll of connection link protocol sequence 2, and the received supervisory information is stored at collection data management I. These transmissions can be made at, for example, a half-duplex start-stop synchronization of 1200B (b/s). In the ML mode, the information collection command is output from the central master station to the master stations, and the supervisory information is received through the master station data transmission 10 under the control of ML mode rpotocol sequence 4 and the received supervisory information is stored at collection dta management and the information collection command is received through the master station data transmission 10 of master station under the controll of connection link protocol sequence 2 and analyzed by ML mode protocol analysis 3, and the supervisory information collected at master station is transmitted therethrough under the control of connection link protocol sequence 2. Also, in this case, these transmissions can be made at, for example, the half-duplex start-stop synchronization of 1200B (b/s).

[0017] The master station polls the slave stations in the SL mode under the management of connection protocol sequence 2 and collects the supervisory information thereat. The center master station polls the slave stations in the SL mode under the management of connection link protocol sequence 2 and collects the supervisory information thereat, and in addition, polls the master stations in the ML mode under the management of ML mode protocol sequence 2 and collects the supervisory information from the slave stations collected by each master station.

[0018] The collection data management function I has, for example, a capacity for storing the supervisory information from 63 stations collected through the slave station data transmission 9 and analyzes the stored supervisory information, and the master station outputs the collected data through the master station data transmission 10 in accordance with the polling from the central master station.

[0019] The supervisory data display 5 displays housekeeping information including the room temperature, open or closed state of doors or the like in each slave station, and supervisory data regarding the state of regenerators, a transmission error, detection data, and the like. The SV system display 6 displays the occurrence of a failure in a supervisory system as the result of analyzing the supervisory information by collection data management. The control operation display 7 receives operation commands for the housekeeping at the input thereof, and the results of the subsequent control are displayed. The equipment alarm output 8 generates an alarm when a failure of the regenerator of the slave station occurs. The line protection operation display II sends an operation command for line protection switch LPSW, such as switching between normal and standby lines, and displays the same.

[0020] The ML mode protocol analysis 3 analyzes the ML mode protocol execution command and sends a command for storage of the received data to the collection data management function I, and for the transmission of the data to be stored.

[0021] Figure 4 is a block diagram showing partially a constitution of the slave station in the embodiment of the present invention, and shows the supervisory functions thereof. In the figure, block 21 denotes a collection data management function storing various supervisory data; block 22 a protocol analysis function which analyzes information collection commands or the like from the master station and controls the transmission of the collected data; and block 23 a detection transmission which, for example, samples input date at intervals of 100 ms, distinguishes whether or not the data is continuously identical, and outputs date indicating the same when the data is continuously identical, and which transmits a short-term information indicating no change in the state, when no change of the state is detected in comparison with the prior state, when being informed of receiving the information collection command by protocol analysis 22. Block 24 denotes a series-parallel and parallel-series conversion (S/P, P/S).

[0022] Block 25 represents an office building alarm input receiving information regarding temperature and alarm information in the office building from each office building facility, e.g., open or closed doors; block 26 represents an equipment alarm input and control which sequentially reads contact information at the equipment and sends control information by which ON or OFF control or the like of switches at each portion is made; block 27 represents an A/D conversion converting an analog detection signal to a digital signal and including a current driving a laser for conversion from an electric to an optical function (when the driving current becomes more than a predetermined value, a deterioration of the laser is determined), and converting another analog detection signal such as a load current for distinguishing overload or the like at an amplifier of a regenerator; block 28 is a bit error data transmission performing a transmission control of the bit error data, which is a bit error rate detected from line data; block 29 is a control output sending control signals to carry out a control of temperature conditions in the office building and to forcibly close doors; block 30 is an equipment alarm output supplying alarm signals from various portions of the equipment; block 31 and 32 are supervisory data transmission functions sending supervisory data from the collection data management block 21 to the slave stations or the master stations located in one and another direction, respectively, for example, at a speed of 1200B by half-duplex start-stop synchronization, or receiving an information collection command; and block 33 is a line protection data transmission function.

[0023] The information collection command from the master station is analyzed at the protocol analysis function 22, and the data stored in the collection data management function 21 is output from one of the supervisory data transmissions functions 31 and 32, which send the data in the direction from which the information collection command is received.

[0024] The above-mentioned collection data management function 21 and protocol analysis function 22 are constituted by a microprocessor and memories, and these blocks are interconnected through a bus.

[0025] In Fig. 5A, Fig. 5B, and Fig. 5C, the connection relationship between the system in Fig. 2 and the slave station in Fig. 4 or the master station in Fig. 3 is shown. Figure 5A shows connection relationship between the terminal station in Fig. 2 and a slave station, a master station. In a regenerator (REG), the slave station and master station are connected to the regenerator having at least one drop insertion function in n lines (this function is almost the same as that of the terminal station). Figure 5B shows an interconnection relationship between the system in Fig. 2 and the master station. Figure 5C shows the case for only the slave stations.

[0026] In Fig. 5A, the supervisory signal multiplexer - (SVOW INF) multiplexes an supervisory information through supervisory data transmission 31 of slave station and slave station data transmission 9, master station data transmission 10 of masterstation and polling command through slave station data transmission 9 in SL mode and an order wire signal from order wire transmitter OW and outputs it to an MUX (multiplexer). At the MUX signals from SVOW INF are multiplexed to main data, such as voice signal, based on the time division mode and inserted in an SV channel and an OW channel on the transmission frame and are transmitted on data transmission line with the main data so that special line for collecting supervisory information is not necessary. Conversely, the SV channel and the OW channel are demultiplexed by the DMUX - (demultiplexer) and the signals are sent to an SV equipment through the SVOW INF. Bit error rate monitor BERMON monitors the rate of error producing on data transmission line at the DMUX by parity check, and bit error data transmission 28 of slave station collects bit error rate information of BERMON. Line protection data transmission 33 of slave station at terminal station transmits the command of switching normal line (NOR) to stand by line (STBY), or vice versa to LPSW under the control of collection data management. In this figure, S-SV is corresponding to C, , C₅, C. , C, , C,, , C_o , C,. and M-SV is corresponding to B, , B, , BS in Fig. 7 and Fig. 9. Fig. 5B shows a repeater station arranged S-SV and M-SV corresponding to C,_o , C,. , B, in Fig. 7 and Fig. 9. As above mentioned, drop insertion function is performed by DMUX and MUX. S-SV (C,4) receives polling commands from No. I up line via OR 41, DMUX 42, SVOW INF 46 and its supervisory data transmission 31 (not shown) and transmits supervisory information to No. 2 down line via its supervisory data transmission 31, SVOW INF 46, MUX 50 and OS 51. S-SV(C,_o) receives polling command from No. I down line via OR 48, DMUX 49, SVOW INF 45 and its supervisory data transmission 31 (not shown) and transmits supervisory information to No. 2 up line via its supervisory data transmission 31, SVOW INF 45, MUX 43 and OS 44. M-SV(B.) transmits polling command to No. 2 down line via its slave station data transmission 10 (not shown), SVOW INF 46, MUX 50, OS 51, and receives supervisory information from No. I up line via OR 41, DMUX 42, SVOW INF 46 and its slave station data transmission 10. And M-SV(B4) also transmits polling command to NO. 2 up line and receives supervisory information from No. I down line via its slave station data transmission 10 and SVOW INF 45. And as the same with Fig. 5A, BERMON 47 monitors error rates of up line and down line, and up line's error rate is transmitted to bit error data transmission 28 of S-SV (C₁₄) and down line's error rate is transmitted to bit error data transmission 28 of S-SV C,o). Order wire tramsiter 52 is connected both SVOW INF 45 and 46. When a repeater station is not arranged M-SV and operates as a slave station, the repeater has only one slave station corrsponding to C₂, C₃, C₄, C₃, C₉, C,_s , C₁₃ in Fig. 7 and Fig. 9. So as shown in Fig. 5C supervisory data transmission 31 connects to SVOW INF 45 and supervisory data transmission 32 connects to SVOW INF 46. In the figure, OR is an optical receiver and OS is an optical sender.

[0027] The polling from the M-SV through the No.1 down line is sent to the M-SV through the No.2 up line. The polling from the M-SV through the No.1 up line is sent to the M-SV through the No.2 down line. Therefore, the M-SV's at both sides can poll asynchronously without signal collision. The M-SV's at both sides have two proper channels.

[0028] Figure 6 shows a relationship between the connection of the S-SV and the M-SV at the same station. Both slave station data transmission 9 and master station data transmission 10 have six connection portions to S-SV. And in SL mode, the data is transmitted and received between slave station data transmission 9 of M-SV and supervisory data transmission 32 of each S-SV's. And in ML mode, the data is transmitted and received between master station data transmission 9 of M-SV and the same. Since M-SV has six connection prtions to S-SV, a maximum of six S-SV's can be applied to the M-SV.

[0029] Figure 7 is a diagram explaining the constitution of a supervisory system, wherein B, to B_s are master stations such as terminal stations, and are provided with the supervisory functions shown in Fig. 3. One of the terminal stations is functions as the central master station. C, to C₁₆ are slave stations, and are provided with the supervisory functions shown in Fig. 4. The master stations B, to B_s are provided with slave stations corresponding to connection portions to each transmission branches. That is, the master station B, is accompanied by C, , the master station B₂ by C_s , C6 , C₈ , and C₁₁, the master station B3 by C₁₃, the master station B₄ by C,_o and C₁₄, and the master station B_s by C₁₆. To expand the number of branches, a maximum of six slave stations can accompany a master station. Hereinafter, each of the master stations B, to B_s has the same function as the master supervisory function, and each of the slave stations C, to C₁₆ has the same function as the slave supervisory function.

[0030] In this description, between one master station and another located next thereto, for example between B, and B2 , between B2 and B, , ... is called a link. So single link mode means that a master station collects supervisory information at slave stations directly within a link connected thereto. And multi-link mode means that supervisory information at master station must pass through a plurality of links in order that a central station collects that.

[0031] The master supervisory function polls including the accompanied slave supervisory function corresponding to the non-installed transmission line. Thus, since the response to the polling is obtained from the slave supervisory function for which the transmission line is installed, when an installation expansion is required, distinction is easily possible. The slave station sends the supervisory information upon receiving a double polling by different master stations. The slave supervisory function appended to the master stations B, to B_s sets the own equipment number and the equipment number of the slave supervisory function at a link end. For example, the slave supervisory function C_s appended to the master station B₂ is set to be able to recognize the slave supervisory function C, at the link end and is set to recognize the presence of the slave supervisory functions C₂ , C₃, and C4 in the middle of the link. These settings can be carried out by using a predetermined area in a network management table.

[0032] Figure 8A and Fig. 8B are diagrams explaining the network management table. The protocol analysis of the master station is provided with an ML mode transference direction network management table shown in Fig. 8A. The table has an area at which the number of links from the central master station MM-SV (the central master 20station in the master stations B, to B_s or the central master station not shown in the figure) to the master stations M-SV (B, to B₄) or the slave stations S-SV (C, to C₁₆) is set, and another area at which the direction (OIH to 06H) (in the case of a maximum 6 directions) to which the ML mode protocol is transferred is set. The initial settings are all non-installed (OOH).

[0033] The direction from which an SIR (setting information transference request) protocol for a non-installed master station M-SV or an SIT (line status information transference) protocol is received, is set in this network management table. At the central master station MM-SV, the direction from which the SIT protocol for the output SIR protocol is received and the number of links LCN are set.

[0034] At the central master station MM-SV, the network management table setting S-SV is provided as shown in Fig. 8B. In the table, the master station M-SV equipment numbers (OIH to OFH) by which a maximum 63 slave stations are managed are set. As an initial setting, after an all non-installed setting (OOH), the SIR (setting information transference request) protocol is carried out for the installed M-SV and S-SV, and the contents of the execution response are set. Where the different master stations M-SV's are doubled up to one slave station S-SV, the master station M-SV having a lesser number of links is set. Therefore, the central master station polls the master station having the lesser number of links, and thus can collect information with a high efficiency.

[0035] Where the change of the setting in the own link, such as an expansion, in the master station M-SV which manages the slave station S-SV occurs, "I" is set in the protocol request information I of the MLRD basic frame (cf. Fig. 10) and is output. Upon receiving by the request information I, the central master station MM-SV carries out the above-mentioned setting information transference request SIR protocol and changes the setting contents. Accordingly, the setting changes in the link, such as expansion, removal, and changes of connections, are easily performed. The data transmission in the ML mode is performed by using the network management tables in Fig. 8A and Fig. 8B.

[0036] In Fig. 7, assuming that the master station B4 is the central master station, when the information at the master station B₂ is collected, the information collection command is output through the master station data transmission 10 by control from the ML mode protocol sequence 4 (cf. Fig. 3). Where, as an inner-link receiving S-SV equipment number ADR of the inner-link basic frame (cf. Fig. 10), the equipment number of the slave supervisory function C, , which is a link end in the direction toward the master station B₂, is set as a receiving M-SV equipment number RMA of the MLCD basic frame, the B2 is set as a sending M-SV equipment number SMA, the B, is set, and the execution command is set on the ML mode transference data MDATI and is output.

[0037] At the slave supervisory function C₈, since the inner-link receiving S-SV equipment number ADR is C₈, the information collection command is self forwarding, and since the receiving M-SV equipment number RMA is B₂, the information collection command is forwarded to the master supervisory function B₂. As mentioned above, since the master supervisory function B, polls the slave supervisory functions C_s , C, , C. , and C,, , when the slave supervisory function C₈ is polled, the prior-received MLCD basic frame is transferred. Whereby, the master supervisory function B₂ analyzes the execution command at the ML mode protocol analysis 3 (cf. Fig. 3), and the data stored in the collection data management I is output through the master station data transmission 10. In this case, the inner-link receiving S-SV equipment number ADR of the inner-link basic frame is set as C,_o. The receiving M-SV equipment number is output as B₄, and the sending M-SV equipment number is output as B₂, through the slave supervisory function C. receiving the information collection command. That is, the execution response is output to the slave supervisory function, which is in the direction from which the execution command is received.

[0038] Accordingly, the central master station B₄ can collect the supervisory information collected at the master station B₂ by polling. Moreover, the master station and the central master station can collect the supervisory information by a comparatively simple constitution, since each station performs the data collection process by polling at a predetermined period.

[0039] Similar to the above, the central master station B₄ can collect the information collected at the master station B, by polling. In this case, the inner-link receiving S-SV equipment number ADR is C, , the receiving M-SV equipment number RMA is B, , and the sending M-SV equipment number SMA is B. In the master station B₂ in the middle thereof, the information collection command is output to all of a the slave supervisory functions appended to the own station without distinguishing the direction of the relaying transference of the information collection command. In the slave supervisory functions C_s , C6 , C, , and C,, , only the slave supervisory function C_s having the designated S-SV equipment number C, in the own link by the inner-link receiving S-SV equipment number ADR, outputs. Thus, at the master station B₂, the direction from which the information collection command is received is stored as the slave supervisory function C, , and when the execution response from the master station B, is received, the execution response is transferred to the slave supervisory function C. , and then is sent in the direction of the central master station B₄.

[0040] As the information collection command, various commands can be prepared, and accordingly, the supervisory information at the slave stations and the master stations which constitute the tandem link can be securely and easily collected.

[0041] Figure 9 shows a constitution of a real system corresponding to that of Fig. 7. Each rectangular box 61, 62, 63, ... 75, 76 shows connecting portion to up line and down line, and rectangular boxies 61, 65, 66, 67, 68, 70, 73, 74, 76 arranged to LTE I, 2, 3, 4, 5 are one side connecting portions and rectangular boxies 62, 63, 64, 69, 71, 72, 75 arranged to REG 2, 3, 4, 7, 13, 9, 15 are two sides connecting portions. And slave station is arranged to each rectangular box.

[0042] Figure 10 is a diagram explaining basic frames. An inner-link basic frame in ML mode comprises a start of text STX function, an inner-link receiving S-SV (slave supervisory function) equipment number ADR, an execution command receiving S-SV or an execution response sending S-SV number MLC-(multi-link-command)/MLR(multi-link-response), a multi-link data MLCD(multi-link-command-data)-/MLRD(multi-link-response-data) function, an end of text function, and a block check character BCC.

[0043] An MLCD basic frame comprises a receiving M-SV (master supervisory function) equipment number RMA, a sending M-SV equipment number SMA, a link counter LCN, and an ML (multi-link) mode transference data MDATI. The receiving and sending M-SV equipment numbers are constituted as 7 bits, wherein four bits OIH to OFH in the 7 bits designate the equipment number. The link counter LCN transmits the contents after adding I, when a receiving M-SV equipment number RMA of a receiving MLC protocol does not designate the equipment itself. In addition, the link counter is set as I when the central master station outputs the contents of the link counter.

[0044] An MLRD basic frame comprises a receiving M-SV equipment number RMA, a sending M-SV equipment number SMA, a link counter LCN, a protocol request information function I, and an ML mode transference data function MDATI. The link counter LCN transmits the receiving content of the MLC protocol link counter as it is. The S-SV denotes the supervisory functions of the slave station, the M-SV denotes the supervisory functions of the master station, and the MM-SV denotes the supervisory function of the further higher rank station, i.e., the central master station.

[0045] Figure II is a diagram explaining the frame of the MDATI, which comprises an S-SV equipment number SA, an ML mode execution command/response C, and an accompanied data MDAT of the command C. The S-SV equipment number constituted by 7 bits and is designated by 5 bits OIH to 3FH.

[0046] Above mentioned inner-link basic frame is for ML made. In SL mode for collecting supervisory information at each slave station, MLCD and MLRD basic frame is replaced to SL mode transference data SDATI which- comprises an S-SV equipment number SA, an SL mode execution command/response C, and an accompanied data SDAT of the command C. The S-SV equipment number constituted by 7 bits and is designated by 5 bits OIH to 3FH.

[0047] Figure 12 is a diagram explaining a sequence of the transmission of the supervisory information in the supervisory system in Fig. 7 and Fig. 9.

[0048] With reference to Fig. 10, Fig. II, and Fig. 2, the sequences of the ML mode and SL mode in the arrangement of Fig. 7 and Fig. 9 are explained.

(I) Pol (Single-Link-Command)

[0049] Pol (SLC) is a polling to the S-SV (C₁₄) in the single link (SL) mode by the MM-SV (B₄). In this case, the transmission frame is the inner-link basic frame in Fig. 10, and the MLC/MLR and the MLCD/MLRD portions are replaced by SDATI, which is similar to the MDATI. The SDATI consists of SA, C, and SDAT. The ADR portion is set by the S-SV having the equipment number C₁₄.

(2) RSP (Single-Link-Response)

[0050] RSP (SLR) is a response signal by C,.. The changing information detected at the detection transmission 23 in Fig. 4 is output. The transmission frame is the same as the Pol (SLC) but ADR is set by the M-SV having the equipment number B₄ and the SA is C,..

(3) Pol (MLC)

[0051] Pol (MLC) is a polling in the multi-link mode of MM-SV (information collection from B₅). The transmission frame is the MLCD basic frame plus the STX, ADR and MLC at the top thereof. ADR is C₁₆, MLC is C₁₆ , RMA is B₅, SMA is B₄, and LCN is I. MDATI consists of SA, C, and MDAT.

(4) RSP (SLC + MLC)

[0052] The transmission frame consists of STX, ADR, SA, C, SDAT, MLC, RMA, SMA, LCN, SA, C, MDAT, ETX, and BCC. ADR is C₁₆, MLC is C₁₆, RMA is B₅, SMA is B₄, and LCN is I. The C,₆ transmits the collection data of the equipment - (SDATI) by polling from B₅ and the ML mode frame from B₄.

(5) Where B. collects the information at B, through B,

[0053] The frame consists of STX, ADR, MLC, RMA, SMA, LCN, MDATI, EXT, and BCC. ADR is C, , MLC is C, , RMA is B, , SMA is B₄, and LCN is I. At first, the information is sent to C_o.

(6) RSP (SLR + MLC)

[0054] By polling from B₂, C, transmits SLR + MLR in the same way as in item (4).

(7) The supervisory data transmission 32 transmits the MLC to all of the dependent slave stations C_s , C, , C₆, and C,, , when the information is not itself forwarded. LCN is added with I. Where there is no relationship of the information, there is no processing, and thus the efficiency of the own polling increases and the load is decreased. C_s recognizes the presence of C, (MLC) in its own link (slave station at opposite end), and accordingly, ACK is sent back. B₂ only memorizes the reception of the command from C₂.

(8) C_s transmits SLR + MLC by polling from Bl.

(9) Po5 (MLR)

[0055] The frame consists of STX, ADR, MLC, RMA, SMA, LCN, and others. ADR is C. , MLC is C_s , RMA is B. , SMA is B, , and LCN is 2.

(10) (II) (12)

[0056] By polling from B₂, B₂ collects SLR + MLR from C_s MLR is transferred immediately to C₃ as memorized at the last time. C, transmits SLR + MLR by polling from B. , and B4 collects the data at B,. B4 has recognized the relationship between B, and LCN by the network management table, and thus, by comparing it with the receiving MLR frame, B₄ confirms normal reception.

[0057] As above mentioned, the M-SV devotes itself to own polling and the S-SV only controls the response for polling, and thus, the polling efficiency is increased.

Claims

I. A supervisory system in a communication system having a plurality of repeater stations, a plurality of terminal stations, and transmission lines, the repeater stations and the terminal stations being connected in tandem through the transmission lines, wherein

each of the repeater stations and the terminal stations is comprised of respective supervisory equipment, part of the supervisory equipment being used as a master station and the remaining supervisory equipment being used as a slave station, one of the supervisory equipment at the master stations being used as a central master station, and the supervisory equipment is formed by a logical hierarchical configuration,

the slave station located between the master stations being polled therefrom and the slave station transmitting its own managing supervisory information to the respective master stations,

the central master station polling each of the master stations, and the master station transmitting the collected supervisory information to the central master station.

2. A supervisory system as set forth in claim I, wherein

each of the master stations and the central master station comprises a slave station function corresponding to the connecting portions between the repeater station and the terminal station, and the transmission line,

the master station and the central master station poll the stave station function and collect the supervisory information.

3. A supervisory system as set forth in claim 2, wherein the central master station comprises a single link mode in which the central master station polls the slave stations and collects the supervisory information as a master station, and a multi-link mode in which the central master station polls each of the master stations and collects the supervisory information thereat.

4. A supervisory system as set forth in claim 3, wherein in the multi-link mode, the central master station polls the slave station functions of the adjacent master stations, the slave station function transmits the supervisory information receiving the polling from the master stations to which the slave station function itself belongs, and the slave station function outputs information of the presence of the polling by the multi-link mode from the central master station.

5. A supervisory system as set forth in claim 4, wherein when the master station detects the polling to itself in the multi-link mode, the master station transmits the supervisory information to the slave station function of the central master station, and the slave station function transmits the supervisory information from the master station by the polling from the central master station.

6. A supervisory system as set forth in claim 4, wherein when the master station detects the polling to another master station in the multi-link mode, the master station outputs information of the presence of the polling by the multi-link mode from the central master station to all of its own slave station functions, the master station repeats the polling by the multi-link mode from the central master station to the respective master station in response to the slave station function corresponding to the connecting portion of the transmission line coupled to said respective master station.

Drawing